Control swtich



Dec. 17, 1957 I. A. DE KRAMER CONTROL SWITCH Filed Oct. 12, 1954 FIG. I.44 u I3 37 25 3|A 30A INVENTOR. LADE KRAMER HIS ATTORNEY United ratesPatent CONTROL SWITCH Isaac A. De Kramer, Churchville, N. Y., assignorto General Railway Signal Company, Rochester, N. Y.

Application October 12, 1954, Serial No. 461,789

2 Claims. (Cl. 200-106) This invention relates to control switches andmore particularly to a type of switch which has a large complement ofcontacts and is still compact in design so far as mounting space isconcerned.

As an example, control panels for railway traffic control machines areusually marked out with various track diagrams and illustrate varioustrack switch and signal locations, each of these locations having acontrol switch mounted adjacent thereto on the panel for controlling theapparatus located at the actual track location in the field. These trackdiagrams are of necessity small and crowded close together on the panel,and the control switches are mounted so that only the control buttonappears on the front of the panel while the contacts and wiringconnections are located in the rear. This requires a control switchwhich is small in cross section to permit the required number to bemounted on the panel.

One of the objects of the invention is to provide such a switch which iseasily accessible for facilitating adjustments of the contact fingersand making wiring connections.

A further object of the invention is the provision of a spring latchlocking means with an electro-magnetic release whereby the controlbutton operating means may be latched in one or both extreme positionsby a separate means for a selected interval of time.

A still further object of the invention is the provision of a switchstructure which can be assembled or altered to present differentcombinations of functions merely by adding or removing some of theparts, the basic assembly remaining the same in all cases.

In describing the invention in detail, reference will be made to theaccompanying drawing in which like reference characters refer to likeparts, and in which:

Fig. l is a top plan view of a push button switch which is provided withan electric latch, certain parts being broken away for clearness, andshown mounted on a control panel;

Fig. 2 is a side sectional view of the switch shown in Fig. 1 and takensubstantially on the line 22 of Fig. 1;

Fig. 3 is a front view with the panel partly broken away to show theswitch mounting;

Fig. 4 is an end sectional view taken on the-line 4-4 of Fig. 2 andshows the mounting for the contact operating cam block;

Fig. 5 is an end sectional view taken on the line 55 of Fig. 2 and showsthe spacing of the cam grooves in the contact operating cam block;

Fig. 6 is an end sectional view taken substantially on the line 66 ofFig. 2 and shows the contact block structure and mounting means;

Fig. 7 is a view similar to Fig. 2 except modified to show the springlatching means operable for both extreme positions, and;

Fig. 8 is another modification of Fig. 2 showing the spring latchingmeans and the push button spring return removed to present a push-pulltype of switch.

- Referring now more particularly'to Figs. 1 to 6 incluice sive, themain body structure of the push button switch consists of a frontbearing block 11 and a rear contact block 12, an upper frame member 13and a lower frame member 14. The four units form a boxlike structurefastened together by screws 15 and tap bolts 16.

The front bearing block 11 provides the mounting means for the controlswitch and houses the push button means. A circular threaded portion 17of this hearing block 11 passes through a hole in the panel P and theswitch is held in place by means of a clamp nut 195. A key portion 19 isprovided which fits into a keyway in the panel P to locate the switchproperly in an upright position and prevent it from turning. The bearingblock 11 is also provided with a hole to provide a bearing for the pushbutton rod 20. This hole is enlarged as shown at 21 to provide space fora compression spring 22 and the shank part of the push button 24. Thepush button 24 is fastened to the rod 20 in any suitable manner, such asby a set screw 23. The compression spring 22 surrounds the small portionof the push button rod 20, one end bearing against the shoulder formedby the shank part of the push button 24 while the other end bearsagainst a shoulder formed at the inner end of the enlarged hole 21.

A contact operating cam block 25 of insulating material is locatedbetween the upper and lower frame mem bers 13 and 14 and next to thebearing block 11. This cam block 25 is substantially rectangular inshape and is fastened to the push button rod 20 by means of a set screw26 (see Fig. 4). In the normal position of the push button, thecompression spring 22 would cause the cam block 25 to bear against thebearing block 11. The enlarged head of push button 24 will limit themovement of the push button and cam block 25 in the other direction whenoperated, by reason of the enlarged head coming to a stop against thecircular portion 17 of the bearing block 11. The cam block 25' isprovided with upper and lower bosses or pads which act as guides andspace the cam block 25 between the upper and lower frame members 13 and14 in a manner to allow a sliding fit.

The contact supporting block 12 is made up of two interchangeable blocksof insulation, each having a complement of round wire type contactfingers molded therein and are provided with a complement of V-shapednotches 27 on one side thereof, each notch located directly in line witha contact finger. These two blocks are fastened together with hollowrivets 28 (see Fig. 6) in such a manner that the V-shaped notches faceeach other and serve to clamp an intermediate wire type contact finger29 in place between the two blocks. This method of assembly provides agroup of contact units each having a front contact finger 30 and a backcontact finger 31 with an intermediate movable contact finger 29 locatedbetween them. The assembled contact block 12 also forms a part of theframe work as previously mentioned and is held in place by the tap bolts16 which pass through the lower frame member 14 and the hollow rivets 28of the contact block 12 and are threaded through the upper frame member13.

The contact fingers 29, 30 and 31 pass through the contact block 12 andare provided with small fiat portions within the molded block 12 toprevent any loosening and turning. The short ends of the contact fingers29, 30 and 31 which protrude from the rear of the block 12 are used tofacilitate wiring connections or plug coupling as will be explainedhereinafter. The long ends of the contact fingers protruding from thefront end of the contact block 12 constitute the contacting means formaking and breaking circuits. The contacting tips of the front and backcontact fingers 30 and 31 are formed hook shaped as shown at 30A and 31Aso that they overlap the movable contact finger 29. This also provides aconvenient place for adjusting contact pressures which is done bybending these tips either away or towards the movable contact finger 29.

In the normal position of an intermediate movable contact finger 29 itis biased against a front contact finger 3%. Its extreme end is bent toform a curved cam sur face 32 which cooperates with a stepped cam groove33 formed in'the contact operating cam block 25, a groove being providedfor each contact finger 219. As shown on the drawing, when the pushbutton is pushed inward, the contact finger cam surface 32 would strikethe slanted portion 34 of the cam groove 33 and be forced downward untilthe cam surface 32 came to rest against the fiat portion 35 of the camgroove in this position the movable contact finger 2? willhavc brokencon act with the front contact finger and made contact with the backcontact finger 31. Upon return of the push button 24 and the cam block25 to their normal positions, the movable contact finger 29 would movefrom its back contact position to its front contact position by reasonof its normal bias.

Referring now to the spring latching means and the electro-magneticrelease as provided in Figs. 1 to 6 inclusive, it can be seen byreference to the drawing that this is a separate sub-assembly which isfastened to the framework of the control switch by means of the tapbolts 16 and nuts 36. A rectangular shaped opening 37 is provided in theupper frame member 13 to facilitate the mounting of the latch assembly.A similar opening 38 is made in the lower frame member is to permitadjustments to be made on the contact fingers, etc. A groove 39 is alsoprovided in the top surface of the cam block 25 to form a shoulder whichwill cooperate with the spring latching means.

In general, this spring latch structure and electromagnetic releasecomprises a main magnetic yoke and support 40 on which is mounted a coil(if and a pole shoe 42, also a non-magnetic spring type bronze armaturehinge 43 to which is mounted an armature of magnetic material. A bronzeshim & is placed between the armature hinge 43 and the mounting end ofthe yoke 40 and the three parts are riveted together with rivets 46 (seeFig. 6) to form one unit to facilitate mounting and handling. Thisbronze shim acts both as a residual air gap means and also as a part ofthe hinge means. A non-magnetic bronze shim 4'7 is also placed over thebottom face of the pole shoe 42 to form a residual air gap between thepole shoe 52 and the armature 4 5- when the armature is in a closedpositition. A hook shaped latch member 48 is fastened to the free end ofthe armature Mr and is positioned to cooperate with the shoulder formedby the groove 39 in the cam block 25.

The armature 44 is normally biased to an open downward position by meansof a force exerted by its bent spring hinge support 43 and in thisposition, the hook on the end of the latch member 33 will bear againstthe top face of the cam block 25, acting as a. stop for the armature 44.When the push button 24 is pushed inward to the limit of its travel, thecam block 25 would operate the contact fingers 29 as previouslydescribed. This movement of the cam block 25 would place the groove 39directly under the hook shaped end of the latch member 48 so that thedownward bias of the armature 44 would drop the hook into the groove 3?.Upon release of the push button 24, the compression spring 22 would tendto return the push button 24 to its normal position but this would beprevented because the hooked end of the latch member 48 would catch onthe shoulder formed by the groove 39. In this position the back contacts29--31 would remain closed until such time as the coil 41 becameenergized through some external control circuit, whereupon the armature.44 would pick up and release .the cam block 25. The compression spring22 4- would then return the push button and its associated contactfingers to their normal positions.

As shown in the drawings, there has been chosen as a standard a supplyof six front and back contact combinations although it should beunderstood that this is merely typical. In most cases, this would befound to be more than adequate and where desired, the two outside frontcontact fingers 30 may be cut off and flattened as shown at 49 tofurnish terminals to which the coil wires 5f may be soldered, thusconducting the current to the outside terminal where it may be connectedto external wires or plug coupled the same as the contact fingers.

As previously mentioned, the terminal block ends of these wire typecontact fingers 29, 3t), 31 may be of any desired form to meet theparticular requirements for making external wire connections but in thedrawings they have been shown pointed to receive a plug coupler.

The plug coupler unit comprises a block of insulation 51 which is fittedwith hollow receptacles 52, the inner part of the receptacles 52cooperating with the ends of the contact fingers 29-30-31 and the outerpart of the receptacles 52 receiving the ends of the external wires 53which are soldered therein. A knurled screw 54 is provided which threadsintoi the contact block 12 to hold the plug coupler in place aftercontact has been made. The upper half of the insulation block 51 islarger than thelower half so that the plug coupler can only be pluggedin one way, the extension 55 on the lower frame member 14 preventing theblock 51 from being inserted when turned around Referring now to themodified Fig. 7, in some uses of the push button switch it may bedesired to lock up or latch the push button 24 in its release positionor even both the release position and the operated position. By merelyadding an additional groove 56 in the top surface of the cam block .25and locating said groove 56 directly under the hooked end of the latchmember 48, it can be seen that the normal downward bias of the armature44 would force the hooked end of the latch member 48 into groove 56.This would prevent movement of the push button 24 and its associated camblock 25 so that the movable contact fingers 29 would not be operateduntil such time as the coil 41 became energized by a proper time delaycircuit. The armature 44 would then pick up, the latch 48 releasing thecam block 25 to allow normal operation of the movable contact finger 29.

Referring now to the modification shown in Fig. 8, there has beenillustrated a simple form of a push-pull switch wherein the compressionspring 22 has been eliminated and the push button head 24A has beenslightly modified to providea control knob with a grip. In this form ofthe invention, the control knob is first pushed inward to cause movementof the movable contact finger 29 to its back contact position whereuponthe cam face portion 32 ofthe movable contact finger 29 will assume andhold a position wherein it will dwell against the fiat portion 35 of thecam groove 33 in the cam block 25. When the push button 24A is pulledout to its original position, the bias of the movable contact finger 29will return it'to its front contact position.

It should be understood, of course, that the push-pull type of operationcould also be used on the other modifications already shown anddescribed which incorporate the electric latching means. It should alsobe noted that all the forms have the same general construction withregard to frame work, mounting means, contact structures, etc; and thatthey differ merely to the extent to which certain parts are removed oradded to obtain the structure desired to perform the functions requiredfor a particular installation.

Having thus shown and described several forms which the invention canassume, it is desired to be understood that other modifications could bemade to obtain the same results without departing from the spirit orscope of the invention.

What I claim is:

1. A push button control switch comprising in combination, a box-likestructure consisting of an upper and a lower frame member each fastenedto a bearing block at one end and a contact block at the other end, acam block slidable longitudinally within said box-like structure, saidblock having a groove in its upper surface normal to its direction ofmovement and having a plurality of longitudinal stepped grooves in itslower surface, an operating rod journaled in said bearing block andconnected at one end to said cam block, the other end of said rod havinga push button knob secured thereto protnlding from said bearing block, acompression spring surrounding the midposition of said rod within saidbearing block biasing said rod in a particular direction axially, apluralty of groups of contacts mounted in said contact block, each ofthe groups of contacts having at least one fixed contact finger and acooperating movable contact finger, each of said movable contact fingersextending into and cooperating with one of said stepped cam grooves, alatch disposed above said cam block, said latch having a centralmagnetic portion secured at one end to a strip of resilient nonmagneticmaterial, said strip of nonmagnetic material being secured to saidboxlike structure and being effective to bias said latch against saidcam block, said latch having a detent secured at the other end directeddownwardly for engagement with said slot formed in the upper portion ofsaid cam block, and an electromagnet secured to said box-like structureabove said latch and having a U-shaped core structure cooperating withsaid central magnetic section of said latch for actuation of said latchto disengage said latch from said slot in the upper portion of said camblock.

2. A push button control switch comprising, a framework consisting ofupper and lower longitudinal frame members fastened at their ends to abearing block and a contact block respectively, a cam block slidablelongitudinally within said structure, said block having a transversegroove in its upper surface and having a plurality of longitudinalstepped grooves in its lower surface, an operating rod journaled in saidbearing block and connected at one end to said cam block, the other endof said rod having a push button knob secured thereto and protrudingfrom said bearing block, a compression spring surrounding themid-position of said rod within said bearing block biasing said rod in aparticular direction axially, a pluralty of groups of contacts extendingthrough said contact block and secured therein, each of the groups ofcontacts having at least one fixed contact finger and a cooperatingmovable contact finger, each of said movable contact fingers extendinginto and cooperating with one of said stepped cam grooves at one end,plug coupling means comprising an insulating block having receptaclesarranged therein to cooperate with ends of the contacts protruding fromsaid contact block, a latch disposed above said cam block forcooperation with said transverse slot in said cam block, said latchhaving a central mag netic portion secured at one end to said contactblock by a strip of resilient material, said latch having a detentsecured at the other end thereof disposed downwardly for engagement withsaid transverse slot in said cam block, and an electromagnet secured tosaid contact block above said latch and having a U-shaped corecooperating magnetically with the magnetic portion of said latch foractuation of said latch to disengage said latch from said transverseslot in the upper portion of said cam block.

References Cited in the file of this patent UNITED STATES PATENTS430,748 OConnell June 24, 1890 1,096,913 Hill May 19, 1914 1,149,787Sebok Aug. 10, 1915 1,310,111 Ancotti et al. July 15, 1919 1,418,748Tregoe et a1. June 6, 1922 2,289,736 Snavely et al. July 14, 19422,471,568 Harrison May 31, 1949

